1. Technical Field
The present invention relates to a position estimation apparatus and a computer readable medium storing a position estimation program. In particular, the present invention relates to a position estimation apparatus and a computer readable medium storing a position estimation program for estimating the position of a mobile object.
2. Related Art
Heretofore, a mobile object positioning device that finds a navigation position of a mobile object from a plural pseudo-ranges from navigation satellites, a positioning navigation section, an inertial navigation section and a Kalman filter, has been proposed (see Japanese Patent Application Laid-Open (JP-A) No. 2006-208392). The mobile object positioning device described in JP-A No. 2006-208392, obtains estimated Doppler values by calculating relative velocities of the mobile object with respect to the navigation satellites from, measured Doppler values between the navigation satellites and the mobile object, a navigation almanac, and output of the Kalman filter. Further, the mobile object positioning device also includes a satellite information selection section, which outputs selected pseudo-ranges from among the plural pseudo-ranges, and a pseudo-range estimation section, which computes and outputs estimated pseudo-range values from carrier wave phase information obtained from the navigation satellites, the selected pseudo-ranges, and output of the Kalman filter. Further, the positioning navigation section inputs the estimated pseudo-range values, and outputs positioning navigation velocities and positioning navigation positions. The Kalman filter finds estimated status values from estimated pseudo-range values, the output of the position navigation section, and output of the inertial navigation system.
However, in the above technology described in JP-A No. 2006-208392, a movement direction of the mobile object may not be estimated by the inertial navigation section estimating the trajectory of the mobile object. Therefore, with this technology, it is necessary to estimate the direction when synthesizing information with the positioning navigation section. Furthermore, the positioning navigation section only inputs pseudo-ranges for estimating positions. Therefore, errors occur at epoch intervals and accuracy of the position estimation is inconsistent.